Production of multifunctional granular medium by partial activation of partially decomposed organic matter

ABSTRACT

A process for the production of low-temperature activated or partially activated partially decomposed organic matter for use as an ion-exchange medium comprising the steps of granulating partially decomposed moisture-bearing organic matter, drying the granules and activating the granules at a temperature of about 175-520° C., wherein the granule has a hardness and cation-exchange capacity suitable for a particular application desired.

FIELD OF THE INVENTION

This invention relates generally to production of a partially physicallyactivated granular media for use in ion-exchange processes, and moreparticularly, to production of activated carbon media using naturalorganic materials as sources.

BACKGROUND OF THE INVENTION

Ion exchange is generally defined as a reversible chemical reaction inwhich ions are exchanged between a solution and an insoluble solid. Morespecifically, it is a type of filtration in which an ionized compound orelement changes place with another ionized compound or element on thesurface of a medium. The term “ion-exchange capacity” describes thetotal available exchange capacity of an ion-exchange medium, asdescribed by the number of functional groups on it.

The process of ion exchange is useful over a broad range ofapplications, and may generally be categorized as either anion or cationexchange. Ion exchange is most frequently used to achieve high-puritywater (including softening, deionizing, water recycling, and heavymetals removal and recovery from wastewater) and in chemical-relatedprocessing. Ion-exchange media are also useful in chromatography,catalysis, electrochemical processes, the creation of super acids andsuper bases, and for the separation, concentration and/or purificationof ionic species, pharmaceutical separations technology, the treatmentof radioactive waste, sugar refining, etc. These materials take avariety of forms, including naturally occurring ion exchangers,synthetic ion exchangers, composite ion exchangers, and ion-exchangemembranes.

Most typically, ion-exchange resins are used. The most common form of anion-exchange resin is a synthetic insoluble matrix of styrene anddivinylbenzene copolymers cross-linked to form beads between 0.03-1.0mm. The beads must be activated to function as ion-exchange material.The beads can be converted to cation-exchange resins through sulfonationor anion-exchange resins through chloromethylation. Ion-exchange resinsare capable of removing heavy metals, such as lead and mercury, fromsolution and replacing them with less harmful elements such as potassiumor sodium. The process for the production of these resins is expensive.The product resin beads are also susceptible to fouling due to organiccontaminants in the water flow. This necessitates the use of activatedcarbon or other removal technologies prior to ion-exchange treatment,only further complicating the process and adding to the cost.

Developmental approaches to the production of an activated carbon mediainvolve using natural organic materials as a source. Examples of suchorganic materials include a variety of vegetable materials, softwoods,cornstalks, bagasse, nut hulls and shells, various animal products,lignite, bituminous coal, straw, anthracite and peat. These processeshave largely focused on either chemical activation (e.g., sulfonation orchloromethylation) or full physical activation of the starting materialat high temperatures. It is known in the art to convert sources such assawdust, wood, or peat into an adsorber by chemical activation. Forexample, peat is impregnated with a strong dehydrating agent, such asphosphoric acid or zinc chloride, mixed into paste and then heated to atemperature of 500-800° C. to activate the peat. The product is thenwashed, dried and ground to a powder. In such a process, the resultantproduct generally exhibits a very open, porous structure that is idealfor adsorption of large molecules. Additionally, a process of steamactivation, also known as physical activation, is typically employedwith sources such as coconut shell and bamboo. The starting material isoften activated by exposure to steam or carbon dioxide at hightemperatures. Temperatures that have been used in the art include about650-1200° C. These processes do not produce a media with a usableion-exchange capacity.

One of the most significant challenges in producing an ion-exchangemedium from natural, organic constituents is achieving a balance betweenthe physical integrity of the form of the ion-exchange medium and theability of the medium to serve as an ion-exchanger. The source of thestarting material and the method of producing a medium from theprecursor are the two most important variables determining theusefulness of the final product as an ion-exchange medium. Importantly,the process used to activate or partially activate the organic materialwill also determine the hardness of the resultant granule and itsability to function as an ion-exchange medium.

One significant disadvantage of the prior art is related to theresultant medium's capacity to function as an ion-exchange medium.Partially decomposed organic starting material inherently possessesion-exchange characteristics; however, the material often loses itsion-exchange functionality during pyrolysis. Pyrolysis is simply thechemical decomposition of a substance by the exposure of extreme heat.Most natural organic ion exchangers tend to have weak physicalstructures making their application possibilities limited. Because theorganic material is prone to crushing, it does not stand up to the oftenrigorous processes used in ion-exchange applications. Additionally, manyknown processes include the step of carbonization either prior to orconcurrent with activation. Carbonization may cause considerableshrinkage and weight loss of the feedstock. Organic sources alsogenerally have non-uniform physical properties. Naturally occurringorganic ion exchangers are unstable outside a moderately neutral pHrange. Finally, such organic ion exchangers tend to be prone toexcessive swelling and peptizing.

Natural inorganic ion exchangers also have a number of disadvantages.They, too, tend to have relatively low ion-exchange capacities. Likenatural organic ion exchangers, natural inorganic ion exchangers tend tohave low mechanical durability. Because they are prone to degradationwhen exposed to certain chemicals in solution, such as oxidizing agents,it may be necessary to pretreat natural inorganic ion exchangers.

The use of synthetic organic ion-exchange resins similarly hasdisadvantages. Importantly, resins generally have the disadvantage offoulant formation on the resin beads. Ion-exchange material removes somesoluble organic acids and bases while other non-ionic organics, oils,greases, and suspended solids remain on the surface of the resin. Thisprocess is known as fouling. Foulants can form rapidly and cansignificantly hinder performance of the system. Cationic polymers andother high molecular weight cationic organics are particularlytroublesome at any concentration. For certain types of resins, even 1ppm suspended solids can cause significant fouling over time. As such,prefiltration upstream of the ion exchange might be required to removeelements, such as colloidal silica, iron, copper, and manganese that cancause fouling of the resin. As organic contaminants begin to build up onthe surface of a resin, the flow of other particles and bacteria is alsodiminished. The costs of pretreatment can be significant.

Additionally, resins require regeneration once the ion-exchange siteshave been exhausted, for example, as feedwater flows through a bed.During regeneration of a cation resin, cations that were previouslyremoved are replaced with hydrogen ions. A step known as “backwash” isoften employed during regeneration so that any organic contaminantbuild-up in the resin can be relieved allowing free flow through theresin. Chemically regenerated ion-exchange processes known in the artuse excessive amounts of regeneration chemicals, require periodic andsometimes even ongoing treatment, and disposal of the chemical waste.The processes can be complex and expensive to operate. There is still aneed for a process with decreased chemical requirements in theproduction of ion-exchange media.

While the processes known in the art for the preparation of ion-exchangematerial from natural solid organic material have been useful forcertain ion-exchange applications, for particular applications it isnecessary to increase the hardness of the resultant ion-exchange mediumwhile minimally sacrificing the media's cation-exchange capacity in theprocess. It is necessary to develop a process for the low-costproduction of an ion-exchange medium that has good ion-exchangecapacity, organics adsorption capabilities, and improved strength suchthat the medium may be used in a wider range of applications.

The present invention is an improved process for the production of anion-exchange medium which possesses increased physical integrity of themedium without compromising the natural cation-exchange capacity of thestarting material.

This invention is related to a natural organic starting material, and inparticular to the use of decomposed or partially decomposed organicmatter. More specifically, a preferred starting material is peat or leafcompost material. Unlike other types of organic materials found innature, peat is naturally partially carbonized. Because of this inherentcharacteristic, peat naturally possesses a cation-exchange capacity ofapproximately 120 meq/100 g. It has been discovered that much of thenaturally occurring high cation-exchange capacity may be retained if thepeat is subjected to either steam, carbon dioxide, nitrogen or otherinert media at low activation temperatures in an inert environment.

In general, enhanced mechanical strength and dimensional stability havebeen achieved when decomposed or partially decomposed organic matter hasbeen partially physically activated at low temperatures. The resultantmedium will also possess enhanced organic contaminant retentioncapabilities when in wastewater. The present inventive processadditionally has been found to decrease the amount of leaching intotreated water from tannins that are naturally present in certainstarting materials. These improvements in the process permit theresultant partially activated media to be used in a broader range ofapplications than those seen in the prior art.

As used herein, the following terms have the meanings given below,unless the context requires otherwise.

The term “mEq” means milliequivalents. The equivalent is a common unitof measurement used in chemistry and the biological sciences. It is ameasure of a substance's ability to combine with other substances. The“equivalent” is defined as the mass in grams of a substance which willreact with 6.022×10²³ electrons. Another way of defining an “equivalent”is the number of grams of a substance that will react with a gram offree hydrogen. The equivalent weight of a given substance isapproximately equal to the amount of substance in moles, divided by thevalence of the substance. Because, in practice, the equivalent weight isoften very large, it is frequently described in terms ofmilliequivalents (mEq). A mEq is 1/1000 of an equivalent.

The term “hardness” means a property of the granular medium's ability toresist attrition during handling and operation. The “hardness number” isa measure of this property and is determined by way of the “Ball-PanHardness” test. The higher the value, the less the losses in uses. Acertain amount of material is put into a pan, together with some steelballs, and shaken for a defined period of time. The material is weighedbefore and after the shaking to determine the amount of attrition. Thepercent of original material that remains after shaking is the “hardnessnumber.” The term “iodine number” means an equivalent to the surfacearea of activated carbon in mg/g. It is the most standard fundamentalparameter used to characterize activated carbon materials performance.

The term “empty bed contact time” means the time required for a liquidin a carbon adsorption bed to pass through a carbon column, assuming allliquid passes through at the same velocity. It is equal to the volume ofthe empty bed divided by the flow rate.

The term “about” means approximately or nearly and in the context of anumerical value or range set forth herein means ±2% of the numericalvalue or range recited or claimed.

The term “ug” means one microgram or one one-millionth of a gram or oneone-thousandth of a milligram.

The term “ng” means nanograms or 1×10⁻⁹ grams or 0.000000001 grams.

OBJECTS OF THE INVENTION

It is an object of this invention to provide a process for theproduction of ion-exchange media with a high degree of control overparticle shape and composition.

Another object is to provide a process that yields an ion-exchangemedium with improved resistance to particle crushing while retainingmuch of the natural ion-exchange capacity of the medium.

Another object is to provide a process that yields an ion-exchangemedium with improved capability for adsorbing organic contaminants fromwater flow.

Another object is to provide a process for the production ofion-exchange media that eliminates the step of complete activation ofthe carbonaceous starting material.

Another object is to provide a process for the production ofion-exchange media that eliminates an additional step of pyrolysis orcarbonization.

Still another object is to provide a process for the production ofion-exchange media that avoids friability of the particles.

Another object is to provide a process for the production ofion-exchange media through low-temperature activation or partialactivation of partially decomposed organic matter.

Still another object is to provide a simpler and more economical processfor the preparation of an ion-exchange medium.

Yet another object is to provide an improved process for the treatmentof peat for its use as an ion-exchange medium in a myriad ofapplications.

Still another object is to provide ion-exchange media possessing usefulcation-exchange capacity.

These and other objects of the invention will be apparent from thefollowing descriptions.

SUMMARY OF THE INVENTION

A process for the production of a multifunctional granular medium isdisclosed. Such process results in the formation of ion-exchange mediaof the type produced by low-temperature activated or partially activatedpartially decomposed organic matter.

In general, the process according to the invention comprises supplyingan amount of partially decomposed moisture-bearing organic matter to agranulating machine, granulating the organic matter, drying thegranules, and activating the granules at a temperature of about 175-520°C. wherein the granule has a hardness and a cation-exchange capacity(CEC) suitable for the desired application.

The organic matter may be screened to remove unwanted particles beforegranulating. Other constituents, such as binders, pH adjusters andreactive compounds may be added to the organic matter beforegranulation. In preferred embodiments, the granule temperature duringthe drying step is about 80-200° C.

Once the granules are dried, a particular size granule is selecteddepending upon the application for which it will be used. This stepcomprises screening granules of varying sizes. In highly preferredembodiments, after the granules are screened to select for a particularsize, the chosen granules are activated by exposing them to steam orcarbon dioxide, nitrogen or other inert media and combinations thereofat a temperature of about 175-520° C. Yet in another preferredembodiments, the chosen granules are activated by exposing them to steamor carbon dioxide, nitrogen or other inert media and combinationsthereof at a temperature of about 230-480° C. In alternativeembodiments, the granule is both dried and activated during the step ofactivation.

In highly preferred embodiments, the granules have a hardness of about80-100% in the Ball-Pan Hardness test. In yet another preferredembodiment, the granules have a Ball-Pan Hardness number of about80-98%.

The decomposed or partially decomposed organic matter to be used in theprocess for the production of ion-exchange material according to theinvention may be compost media, livestock manure, sewage sludge, andcombinations thereof. In preferred embodiments, the partially decomposedorganic matter is compost media. Compost media may be leaf compostmedia, peat, plant by-products, and combinations thereof. In highlypreferred embodiments, compost media is leaf compost media. It mosthighly preferred that compose media be peat.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The low-cost process for the production of a multifunctional granularmedium suitable for use as an ion-exchange media and characteristics ofthe media resulting from such process will now be discussed. Suchprocess results in the formation of ion-exchange media of the typeproduced by low-temperature activated or partially activated partiallydecomposed organic matter. The preferred embodiments described hereinare not intended to be exhaustive or to limit the invention to theprecise form disclosed.

In general, the process according to the invention comprises supplyingan amount of partially decomposed moisture-bearing organic matter to agranulating machine. More particularly, the moisture-bearing organicmatter is peat or leaf compost media. The peat is granulated, dried andactivated. The peat may contain unwanted particles and, as such, it maybe necessary to screen such unwanted particles before granulating.

Other constituents, such as binders, pH adjusters and reactivecompounds, may be added to the peat before granulation. In preferredembodiments, the granule temperature during the drying step is about80-200° C.

Once the peat granules are dried, a particular size granule is selecteddepending upon the application for which it will later be used. The stepof screening for a particular size comprises screening granules ofvarying sizes.

In highly preferred embodiments, after the granules are screened toselect for a particular size, the chosen granules are activated byexposing them to steam or carbon dioxide, nitrogen or other inert mediaand combinations thereof at a temperature of about 175-520° C. In highlypreferred embodiments, the chosen granules are activated by exposingthem to steam or carbon dioxide, nitrogen or other inert media andcombinations thereof at a temperature of about 230-480° C. Inalternative embodiments, the granule is both dried and activated duringthe step of activation.

In highly preferred embodiments, the granules have a Ball-Pan Hardnessnumber of about 75-100%. In yet another preferred embodiment, thegranules have a Ball-Pan Hardness number of about 80-98%.

The decomposed or partially decomposed organic matter to be used in theprocess for the production of ion-exchange material according to theinvention may be selected from the group consisting of compost media,livestock manure, sewage sludge, and combinations thereof. In highlypreferred embodiments, the partially decomposed organic matter iscompost media. Compost media is selected from the group consisting ofpeat, plant by-products, leaf compost, and combinations thereof. In analternative embodiment, compost media is leaf compost media. It is mosthighly preferred that compost media be peat.

Compost media is any decayed organic matter. Plant by-products mayinclude partially decomposed plants, leaves, stalks, and silage, forexample. Livestock manure is the dung and urine of animals. Sewagesludge is solid, semi-solid or liquid residue generated by the processesof purification of municipal sewage. Each of the foregoing sources ofdecomposed or partially decomposed organic matter has innateion-exchange capacity. The ion-exchange capacity inherent to each ofthese sources is significantly similar.

As demonstrated in the examples which follow, by employing a process oflow-temperature activation of partially decomposed organic matter, themedium retains much of its inherent cation-exchange capacity, obtains anincreased capacity for organic contaminants (and some other metals) insolution and has increased strength and durability when exposed towater. These characteristics make the media well-suited for waste waterremediation.

EXAMPLES 1-4 Base Process

Exemplary multifunctional granular media were prepared. Each granularmedium included peat. The peat selected was of a reed sedge typecommercially available from American Peat Technology, Inc. of Aitkin,Minn.

For each of the Examples 1-4, the peat material was first dried to amoisture content of about 40%. Using a granulating machine, thismaterial was then compressed and dried again to a moisture of about 6%.The resultant material was then crushed and sized to a range of about 10to 30 mesh.

Observations with respect to activation temperatures, product yield,cation-exchange capacity, Ball-Pan Hardness number and Iodine numberswere made as noted in each example and in Table 1.

Example 1

A process for the production of a multifunctional granular medium bymeans of partial activation of peat was used. The peat was partiallyactivated at 232° C. for about 30 minutes. The granular materialachieved a maximum temperature of 212° C. with an outlet steamtemperature in the reactor of 132° C. Two pounds of steam were used perpound of product produced. The yield of the product produced was 90% ofthe weight of the granular material input.

The product from Example 1 had a cation-exchange capacity of 120 meq/100g of Cu²⁺. The Ball-Pan Hardness number was 88.6%. The surface area was198 mg/g as determined by the Iodine number.

Example 2

A process for the production of a multifunctional granular medium bymeans of partial activation of peat was used. The peat was partiallyactivated in an inert environment at 287° C. for about 30 minutes.

The granular material achieved a maximum temperature of 260° C. with anoutlet steam temperature of 162° C. Two pounds of steam were used perpound of product produced. The yield of product produced was 90% of theweight of granular material input.

The product represented in Example 2 had a cation-exchange capacity of92 meq/100 g of Cu²⁺. The Ball-Pan Hardness number was 96.9%. Thesurface area was 123 mg/g as determined by the Iodine number.

Example 3

A process for the production of a multifunctional granular medium bymeans of partial activation of peat was used. The peat was partiallyactivated at 343° C. for about 30 minutes. The granular materialachieved a maximum temperature of 326° C. with an outlet steamtemperature of 182° C. Two pounds of steam were used per pound ofproduct produced. The yield of product produced was 80% of the weight ofgranular material input.

The product from Example 3 a cation-exchange capacity of 68 meq/100 g ofCu²⁺. It also had a Ball-Pan Hardness number of 97.3%. The surface areawas 178 mg/g as determined by the Iodine number.

Example 4

A process for the production of a multifunctional granular medium bymeans of partial activation of peat was used. The peat was partiallyactivated at 482° C. for about 30 minutes. The granular materialachieved a maximum temperature of 454° C. with an outlet steamtemperature of 273° C. Two pounds of steam were used per pound ofproduct produced. The yield of product produced was 65% of the weight ofgranular material input.

The product from Example 4 had a cation-exchange capacity of 13 meq/100g of Cu²⁺. It also had a Ball-Pan Hardness number of 76.4%. The surfacearea was 304 mg/g as determined by the Iodine number. TABLE 1 Cation-Maximum Exchange Activation granule Outlet Product Capacity Ball-PanIodine temperature temperature temperature Yield (meq/ Hardness numberExample (° C.) (° C.) (° C.) (wt. %) 100 g) (%) (mg/g) 1 232 212 132 90120 88.6 198 2 287 260 162 90 92 96.9 123 3 343 326 182 80 68 97.3 178 4482 454 273 65 13 76.4 304

It was observed for Examples 1-3 that the cation-exchange capacity andBall-Pan Hardness numbers were within ranges satisfactory for use inion-exchange applications. As the temperature of activation is increasedto about 482° C. as seen in Example 4, the ion-exchange capacity islimited and the Iodine number is significantly higher. A higher Iodinenumber generally indicates a greater adsorptive capacity for organics.Therefore, though the ion-exchange capacity is somewhat compromised atthe higher temperature of activation, a medium such as that seen inExample 4 with an Iodine number of 304 mg/g is better suited for use asan organic adsorption medium.

The data reveal that activation at temperatures at the lower end of therange produces a granular medium with a higher product yield and highercation-exchange capacity than activation at higher temperatures withinthe range. It was observed that the Ball-Pan Hardness number hits itspeak at the level of activation expressed in Examples 2 and 3. Afterthat level of activation was reached, the internal bonds in the granulebegin to break down causing an observed decrease in the hardness number.It was also observed that activation at points along the range producesa granular medium with a Ball-Pan Hardness number that is withinsatisfactory ranges for use as an ion-exchange material.

Example 5

A column of the material produced according to the process described inExample 2 was subjected to an industrialized wastewater containingmercury and other toxic metals in solution. The granular material in thesize range of 10 to 30 mesh was placed in the column in the wettedstate. The wastewater flow rate through the column was maintained atabout a 10 minute empty bed contact time (EBCT). EBCT is the time ittakes for the water to fill the volume of media in the column. Resultsof water analysis before and after granular contact are listed for avariety of metals, including mercury. These results were averaged overone week's time. TABLE 2 Metal Ion Concentration Mercury Copper ZincNickel ng/L ug/L ug/L ug/L Before granular contact 9.3 45.2 95.6 136After granular contact 2.5 10.8 <50 31 Percentage Removal 73% 76% >48%77%

The results for mercury and other toxic metals show the multifunctionalgranular medium by partial activation of partially decomposed organicmatter as claimed is particularly well-suited for polishing wastewaterflows with low concentrations of dissolved heavy metals in an economicalmanner. Due to the low EBCT and high overall cation-exchange capacity ofthe granules (CEC=92 meq/100 g), very little of this material isrequired to treat vast quantities of polluted waters. The high granularhardness (Ball-Pan Hardness=96.9%) is required to withstand water flowrates and long column residence times. All these factors coupled withthe economy of the claimed process show the media is particularlywell-suited for use in metals removal by ion exchange.

Examples 6-11

If examples 1-5 were followed using compost media, leaf compost media,sewage sludge, livestock manure, plant by-products, and combinationsthereof instead of peat, it is believed that similar results would beobtained as those represented in Tables 1 and 2. It is expected that nosignificant modifications, if any, in the method disclosed in examples1-5 would be required using these alternative sources of partiallydecomposed organic matter.

Compost media and peat are substantially similar starting materials;peat is a type of compost media. Other types of compost media, it isbelieved, would yield similar results. Both leaf compost media and plantby-products are also types of compost media. All of these sources ofdecomposed or partially decomposed organic matter possess naturallyinherent ion-exchange capacity. As such, it is believed that usingcompost media, leaf compost media, plant by-products or combinationsthereof as a source would yield similar results as if peat had been usedas the starting material.

It is further believed that sewage sludge would also make a suitablestarting material because it, too, possess substantially similar naturalion-exchange capacity. As such, it is expected that if examples 1-5 werefollowed using sewage sludge, similar results would be obtained.

Likewise, livestock manure possesses inherent ion-exchange capacitycharacteristics making it a suitable decomposed or partially decomposedorganic matter for use as a starting material in the method disclosed inexamples 1-5.

Finally, it is believed that any combinations of compost material,livestock manure, and sewage sludge would render results similar tothose in Tables 1 and 2. The combination of such decomposed or partiallydecomposed starting materials is not expected to significantly alter theresults of the method followed in examples 1-5.

It is believed that the invention has been described in such detail asto enable those skilled in the art to understand the same and it will beappreciated that variations may be made without departing from thespirit and scope of the invention. While the principles of the inventionhave been described in connection with specific embodiments, it shouldbe understood that these descriptions are made only by way of exampleand are not intended to limit the scope of the invention.

1. A process for the production of low-temperature activated orpartially activated partially decomposed organic matter for use as anion-exchange medium comprising the steps of: supplying an amount of thepartially decomposed moisture-bearing organic matter to a granulatingmachine; granulating the partially decomposed organic matter; drying thegranules; and activating the granules at a temperature of about 175-520°C., wherein the granule has a hardness and cation-exchange capacitysuitable for a particular application desired.
 2. The process of claim 1further comprising screening the partially decomposed organic matter toremove unwanted particles before granulating.
 3. The process of claim 1further comprising admixing additives with the partially decomposedorganic matter after screening.
 4. The process of claim 3 wherein theadditives are selected from the group consisting of binders, pHadjusters, reactive compounds and combinations thereof.
 5. The processof claim 1 wherein the granule temperature during the drying step isconducted at a temperature of about 80-200° C.
 6. The process of claim 1further comprising the step of selecting a granule size for a desiredapplication.
 7. The process of claim 6 wherein selecting the granulesize comprises screening granules of varying sizes.
 8. The process ofclaim 1 wherein the granules are activated in an inert environment. 9.The process of claim 8 wherein activating the granule comprises exposingthe granule to steam or carbon dioxide, nitrogen or other inert media,and combinations thereof, at a temperature of about 175-520° C. untilthe desired level of hardness and activation is achieved.
 10. Theprocess of claim 9 wherein activating the granule comprises exposing thegranule to steam or carbon dioxide, nitrogen or other inert media, andcombinations thereof, at a temperature of about 230-480° C. until thedesired level of hardness and activation is achieved.
 11. The process ofclaim 1 wherein the granule is dried during the step of activation. 12.The process of claim 1 wherein the granule has a hardness of about75-100%.
 13. The process of claim 12 wherein the granule has a hardnessof about 80-98%.
 14. The process of claim 1 wherein the partiallydecomposed organic matter is selected from the group consisting ofcompost media, livestock manure, sewage sludge, and combinationsthereof.
 15. The process of claim 14 wherein the partially decomposedorganic matter is compost media.
 16. The process of claim 15 whereincompost media is selected from the group consisting of leaf compostmedia, peat, plant by-products, and combinations thereof.
 17. Theprocess of claim 16 wherein compost media is leaf compost media.
 18. Theprocess of claim 16 wherein compost media is peat.